I want to know which risks I expose to if I start developing web applications using frameworks built around NodeJS? Are they production ready?
Do you have any experiences to share regarding implementation of those frameworks (Go on and develop vs. wait for maturity)?
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short answer: https://github.com/joyent/node/wiki/Projects,-Applications,-and-Companies-Using-Node
node.js is not at 1.0 yet, so things can change. but as you can see many companies are using node.js in production. I wouldn't use it for banking, but it's stable enough to use.
there are frameworks that are being used in production such as expressjs http://expressjs.com/applications.html
I believe the now.js is working on a paid version, so there are likely to be improvements coming.
Data.js is ready to use and has a couple projects posted on it's github page.
Full Speed Ahead is what I say. There's really no point in waiting, your biggest problem isn't that node.js is half-baked(which it's not), but that it's developing at an accelerated rate.
About node.js stability you can refere to this question: online Node.js server
Date.js and Now.js is diffrent story. I don't know them very well.